In Brief:

Sun unleashes another powerful flare

(CNN) -- The sun, exhibiting its most turbulent behavior in years, unleashed on Sunday the fifth most powerful solar flare ever recorded. The flare, considered an X-14 X-ray class eruption, was nearly as strong as a blast in 1989 that triggered the collapse of a major power grid in Canada.

The most recent salvo should do little to threaten electrical or communications systems on Earth or in Earth orbit since it was directed away from our planet, space weather forecasters said.

A flare with an X-20 or higher intensity left the sun on March 2. It was one of the two most powerful blasts recorded since satellites began measuring solar activity in 1979.

The sun, at the peak of an 11-year cycle of solar activity, has in recent months unleashed many powerful solar flares. They are sometimes associated with coronal mass ejections, streams of billions of tons of gas and radiation that, when directed toward Earth, can disrupt satellites and radio communications and produce dazzling auroras.

Space plane prototype conducts test flight

(CNN) -- An unmanned reusable space plane prototype has successfully completed its second free-fall flight, NASA engineers said. The X-40A craft is an 85 percent scale model of the planned X-37, which will launch from the space shuttle and return to Earth like an airplane.

An Army helicopter last week lifted the X-40 to an altitude of 15,050 feet (4,587 meters) from a flight center in Edwards, California. The X-40 was then released and glided for two minutes before rolling to a stop.

NASA technicians used the flight to check onboard navigation, guidance and landing systems. The test concentrated on complex vehicle maneuvers, unlike the first one in March, which focused on a straight-in vehicle approach.

NASA plans at least five more flight tests over the next year. In February NASA stopped development on the problem-plagued X-33, which was planned as the low-cost successor for the aging space shuttle fleet.

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